Butadiene is an important basic chemical, is used as an intermediate for a variety of petrochemicals including synthetic rubbers or electronic materials, and is currently one of the most important feedstock in the petrochemical market for which demand and values keep increasing. Methods of butadiene preparation may involve reactions such as naphtha cracking, n− butene direct dehydrogenation, n-butene oxidative dehydrogenation, etc.
Among these, the butadiene preparation method using oxidative dehydrogenation involves reaction at high temperatures ranging from 300 to 600° C., and the butadiene prepared from such reaction is dissolved in the absorption solvent, from which light gas is separated. After the solvent is removed and distilled, high purity butadiene is obtained. Meanwhile, of the separated light gas, components effective to the reaction are circulated and re-introduced into the reactor, while the rest is discharged out of the system along with purge stream.